The shielding effects of the crack-tip plastic zone

Abstract

In this paper we demonstrate that a plastically deformed zone around a stressed crack tip can be, mechanically, identified with an inclusion of transformation strain by means of Eshelby equivalent inclusion method. Thus, the shielding effect of the plastic zone can be quantitatively evaluated by the present transformation toughening theory. A closed-form solution to determine the change in the stress intensity factor induced by the plastic zone is given both for plane stress and plane strain mode I cracks under small-scale yielding conditions. By using the present solution, the effects of the strain-hardening behavior of the material, the plane stress and plane strain states and the T -stress on the crack-tip shielding effects are identified.

Optimal Bainite Contents for Maximizing Fatigue Cracking Resistance of Bainite/Martensite Dual‐Phase EA4T Steels

“…Figure a presents a variation of r c with V B at Δ K = 12 MPa , indicating that r c increases with increasing V B . Under the same experimental conditions, a larger plastic zone usually helps to reduce FCG rate effectively …”

Numerical analysis of fatigue crack growth using a plastically dissipated energy factor based model

“…On the one hand, the shielding effect induced by the increased plastic zone caused by overload will continue to affect the stress field strength at the crack tip according to the plasticity toughening theory. 53 On the other hand, the overload will change the crack profile, which may affect crack closure, especially for the constant amplitude load with a small load ratio. To further study the reasons for the change of crack growth rate caused by overload and underload, the COD and its change with crack growth are extracted, as shown in Figure 15.…”

Patterned arrangement regulated mechanical properties of hydrogenated graphene

“…To approach it, we first designed four HG sheets with different void shapes (circle, Here, the noticeable amelioration of mechanical properties of defective HG with patterned hydrogenation is proposed to be the result of shielding effect [42] of hydrogenation on stress concentration. On hydrogenated edges, the hydrogenation around void edge will decrease the edge stress under uniaxial loading [43], which is compressive along the edge.…”